Well, we have some news. A leaked build has made its way onto the internet. Strangely enough, WinBeta has noted that:
“…although this build is older than the build released to Insiders last week, it appears 14278 is from a different development branch. This build is from development branch RS1, an internal branch which may have more features checked in for testing.” WinBeta
No new features were found in the build.
UPDATE: The build is from the Enterprise Branch. This explains why it was from a different branch than what Insiders are enrolled in.